US1963917A - Pour test depressor - Google Patents

Description

June 19, 1934. F. H. MacLAREN POUR TEST DEPRESSOR Filed Jan. 18, 1933 2 Sheets-Sheet l INVENTOR r zc/UZfi/acuz/wz ATTORNEY 7 Patented June 19, 1934 UNITED STATES POUR TEST DEPRESSOB Frederick H. MacLaren, signor to Standard Oil Calumet City, Ill., as- Company, Chicago, 111.,

a corporation of Indiana Application January 18,

17 Claim.

This invention relates to pour test depressors and it pertains more particularly to the preparation and use of an improved condensation product which may be added to lubricating oils, transformer oils, etc. for the purpose of lowering their cold tests and improving their viscosity indices.

Most high grade lubricating oils are prepared from paraflin base or mixed base crudes and they therefore contain considerable amounts of wax. This wax normally causes the oil to congeal at low temperatures, to solidify in oil lines, and to render starting difl'icult when used in the crankcase of automobiles in cold weather. To remove enough wax for obtaining extremely low 16 pour points would require diificult and expensive refining processes, and furthermore, the removal of wax impairs the viscosity index (Dean 8: Davis Chemical 8: Metallurgical Engineering, vol. 36, 1929, page 618) of theoil, making it less viscous 20 at high temperatures and/or more viscous at low temperatures. The object of my invention is to 'provide a substance which may be added to a wax-bearing lubricating oil which will lower the pour point of said oil without impairing its viscosity index. In other words, my object is to leave the wax in the oil for the purpose of increasing the quality of the lubricant and at the same time to prevent the oil-wax mixture from solidifying or congealing by the low temperatures at which the oil must be used (usually about +20 to -20 F. in winter).

It is known that naphthenic or aromatic rings with long paraflin side chains have relatively low pour points and high viscosity indices, and that they impart these characteristics to some degree to oils with which they are blended. Products of this general type may be extracted from natural petroleum residuums, or they may be synthetically produced by means of the old and well known Friedel-Craft synthesis in which the aromatic hydrocarbon and the appropriate alkyl compound are made to react in the presence of aluminum chloride. One specific process of this type is described in U. S. Patent 1,815,022, in

which process the Friedel-Craft synthesis or condensation is efiected in the presence of a hydrocarbon diluent, such as kerosene, and in which chlorinated wax is added to a mixture of naphthalene and aluminum chloride. I have discovered that when the Friedel-Craft synthesis is effected under very different conditions than those stated in this patent, I obtain a product which is sometimes 500% more effective as a pour point depressor, a product which diifers '55 chemically in that it is a chlorine-containing 1933, Serial No. 652,285 (Cl. 87-9) compound instead of a hydrocarbon, and a product which may be used in very much smaller proportions, thereby improving the color, the Conradson carbon and the Carbonization Index" (S. A. E. Journal, vol. 29, No. 3 (Sept. 1931) page so 215) of the lubricating oil to which the pour point depressor has been added.

The object of my invention is to provide a pour point depressor which is eifective in reducing the pour points of highly viscous oil. A35 further object is to provide a pour test depressor which will be operative when oil is shock chilled.

A further object is ,to produce a pour test depressor which is effective in very small quantities so that it will not impart an objectionable color 7 and carbon residue to the lubricating oil. In other words, the object of my invention is to provide a depressor which will be efiective in shock chilling as well as slow chilling and which will be many times as efl'ective as pour point depressors heretofore used, so that the minute amounts which are required will not impair the color of the oil or increase its carbon residue.

A further object of my invention is to provide an improved method ofmaking pour point depressors of this particular type and to define the conditions, proportions, etc. of the Friedel-Craft v synthesis so that uniform products may be produced on a commercial scale.

One of the important differences between my process of making pour test depressors of the chlor-wax condensate type and the prior art process lies in the order of combining the reagents in the condensation reaction. The prior art .has taught that the aluminum chloride cat- 90 alyst should be added to the aromatic reagent (naphthalene), and the chlor-wax introduced gradually afterward to control the reaction rate.

I have discovered that better results are obtained by first mixing the aromatic reagent with chlorinated wax and then adding the aluminum chloride at a rate suflicient to produce a violent reaction, thereby regulating said reaction and keeping it under control. It appears that this produces an entirely diflerent type of reaction and gives higher yields of a more effecilve pour test depressor.

I have also discovered that the condensation of chlorinated wax with aromatic substances, such as naphthalene, should be effected in the ab- 10 sence of organic diluents to obtain the best results. However, if diluents are used in the reaction, they should be of the chlorinated type such as C014 and C2H4C1z. I have likewise discovered that the reaction need not be extended over a my temperatures. I have discovered that the desiredproducts should be removed from the reaction mixture by an extracting liquid, preferably a halogenated solvent, hexane or naphtha. Many other features of my process will be apparent as the detailed description of the invention proceeds.

Briefly, I mix about 100 parts of chlorinated wax with about 10 parts of naphthalene. I heat this mixture to about 130-140"v F., and with constant agitation I slowly add to this hot mixture about 10 parts by weight of aluminum chloride powder,the addition of the powder usually taking about 15 to 30 minutes. The rate of adding the aluminum chloride lence of the reaction and should be slow enough to keep the reaction under control. Of course, the aluminum chloride may be added as a slurry, preferably in a halogenated liquid, but in this case it is desirable to use as small an amount of liquid as' possible. I may also add powdered aluminum metal in place of or in addition to the AlCla. I maintain the temperature of the reaction mixture at about 130-140 F. for a period of one to four hours, removing the copious hydrochloric acid fumes therefrom, and I then add to the mixture a relatively large amount of an extracting liquid, such as carbon tetrachloride, chloroform, tetrachlor ethane, etc. in order to reduce the viscosity and facilitate sludge separation. Naphtha may be used as an extracting agent but is not as effective as the halogenated solvents. It will thus be seen that my process is entirely different from the process heretofore employed and I find that the resulting product is also markedly different from any product heretofore produced. a

In the accompanying drawings, which form a part of this specification and in which similar parts are designated by like reference charactars throughout the several views:

Figure 1 is a vertical section through the apparatus employed in my improved process, taken along the lines 1--1 of Figure 2;

Figure 2 is a horizontal section of the same apparatus taken along the lines 2--2 of Figure 1;

Figure 3 is a vertical section taken along the lines 3-3 of Figure 2;

Figure 4 is aflow diagram. steps of my process, and

Figure 5 is a graph showing the efiect of my improved pour point depressor as compared to a commercial pour point depressor which is alleged to be made under U. S. Patent 1,815,022 and which is commonly designated by the trade-mark "Parallow.

For my chlorinated wax I may employ various waxes, such as paraflln, petrolatum, Montan, ozocerite wax, etc., but my best results have been obtained with 130 F. melting point paraffin wax. Good results have also been obtained with heavy parailln oils, particularly with heavy residual oils which have been treated with chemicals or extracted with propane or other solvents for the removal of asphalt. The optimum degree of chlorination is about 10-15%, although excellent illustrating the depressors can be produced with chlorine concentrations as high as 30%. In my preferred embodiment I use a 130 F. melting point paraffin wax havinga chlorine content of about I prefer to use naphthaleneas a condensing agent but I have found that diphenyl, chlorinated diphenyl, fiuorene, phenanthrene,- anthracene,

will depend on the vioother suitable extracting liquid coal tar residues, etc., may also be used. I may also use halogenated naphthalene as a condensation reagent or I may use naphthenic or aromatic compounds equivalent to naphthalene in this reaction. l

About parts of the chlorinated wax are mixed with about 5 to 20, preferably 10. parts of naphthalene. This mixture is introduced into a jacketed chamber 10 which is provided with a hopper bottom 11 and a large gate valve 12 which leads to a residue discharge pipe 13. This lacketed chamber is provided with a cover 14 which is secured thereto by bolts 15 through the registering flanges. Journaled in bearings 16 and 17 is a shaft 18 provided with paddles 19 at its lower end and with a driving means 20 at its upper end so that the mixture of chlorinated wax and naphthalene in the tank may bethoroughly and continuously agitated. The chamber is maintained at a temperature of about 130-140 F. by means of steam coil 21 and about 10 to 15 parts of aluminum chloride are slowly added to the mixture from hopper 22. The addition of al-' uminum chloride should preferably be extended over a period of about 15 to 30 minutes, and during this entire period the mixture should be thoroughly agitated. Large amounts of hydrochloric acid are formed and the mixture usually foams up to three or four times its original volume, so that the chamber should only be about one-fourth full when the batch is started. The hydrochloric acid vapors, HrS, etc. are removed through pipe 23.

After the aluminum chloride has been added the stirring and heating are continued for a period of one to four hours, usually one hour is sufllcient. The mixture is then extracted with carbon tetrachloride, chloroform, hexane or introduced through pipe 24, preferably employing about one-half to two volumes of extracting liquid per volume ofreaction mixture. The extracting liquid is thoroughly stirred and mixed with products in the chamber by means of stirrer 19 and then it is allowed to settle for several hours. I may withdraw the residue by opening gate valve 12 in the manner of a separatory funnel but I prefer to lower the swiveled pipe 25 which is connected by pipe connections 26 to outlet pipe 27 and which is controlled by chain 28, trained over pulley 29 and secured to weight 30. When pipe 25 is positioned just above the sludge level 31 I withdraw the upper liquid 32 through pipe 2'! as hereinabove described. I may then introduce more extracting solvent and I may continue the extractions until all the desirable products have been removed. a v

The extract is thoroughly neutralized and washed to remove undesirable chlorine compounds and loosely bound chlorine, and itis then distilled to remove the extracting liquid. It is not necessary to distil of! unreacted wax products because when the reaction is carried out in the manner described, the amount of these materials left in the product is negligible and has no deleterious effect on the final product. The final residue constitutes my improved pour point depressor and it is characterized by a chlorine content of from two to ten per cent, and usually from three to six per cent.

14: The process may be readily understood from the nated wax to the mixture of naphthalene and aluminum chloride.

The importance of my particular operating conditions may be seen from the following com parisons with blank and Paraflow" treated S. A. E. 40 lubricating oil. In my method I used, in each case, 20 grams of naphthalene, 20 grams of 'AlCla and 180 grams of chlorinated wax (13.75% chlorine) reacted at 130-"-140 F. for four hours:

Solid test F. (A. S. T. M. chilling) 34% de- 1% dcpressor pressor Degrees F. Degree: F. Blank--(no depressor) 33 +33 Par-allow +26 +22 Comparative data-my method:

1. In presence 01200 cc. naphtha +10 l2 2. In presence of no solvent l0 l2 3. In presence of 200 cc. ethylene dichloride 5 16 The effect of my condensation product as a pour point depressor is much more pronounced than that of any depressors heretofore known. The effect of adding various amounts of different pour point depressors to a prediluted oil is illustrated in the graph of Figure 5 wherein the solid tests of a certain lubricating oil are plotted against the percent of depressor necessary for obtaining those pour tests. These particular tests are on an S. A. E. 20 Mid Continent lubricating oil of the type marketed by a large oil company. With no depressor added, this oil had a pour test of 8" F. (a); with 025% of Paraflow this.

pour point was not noticeably affected (b) and with the same amount of my depressor it is reduced to 20 F. (c). When about .1% of the depressors are used it will be seen that Parafiow" will give a pour point of 11 F. (d) while my depressor gives a pour point of about 32" F. (e). When 1.5% of Paraflow is used the pour point is lowered to 26 F. (f) while a similar amount of my product gives a pour point of about 37 F. (g). i From this point both curves turn upwardly due probably to the viscosity of the added material.

This graph brings out several very interesting points. It shows that my depressors produce pour points which are markedly lower than can possibly be obtained'by Paraflow even if used in very large amounts. It shows that a very small amount of my depressor is equivalent to a large amount of Paraflow, 0.025% of my product is more effective than 0.3% of the latter, and 0.05% of my product is more effective than 1.5% of Paraflow. To obtain a good pour point I use less than half the amount of depressor heretofore required, which means that the color of the finished oil is not impaired and the carbon residue (Conradson carbon) and Carbonization Index" of the finished oil is not materially increased.

I have also discovered that my improved pour point depressor is preferentially oil-soluble when the finished oil is given a light clay treat to improve its color. Heretofore the dark colored pour point depressors were deemed necessary inthe finished oil, but I have found that when from onehalf to one percent of my pour point depressor is added to a light lubricating oil and the oil is then percolated through or contacted with clay the color of the oil is markedly improved and the low pour point due to the presence of the depressor is practically unimpaired. When 180 pale oil having a solid point of 30 F. was treated with onehalf percent of my depressor, the solid point was lowered to 40 F. and when the treated oil was percolated through clay, the color of the flnished oil was markedly improved and the solid point was 35 F.

One of the important advantages of my pour test depressing substance is its consistent behavior,

regardless of conditions of chilling the oil. Approximately the same result is obtained when the oil is shock chilled as when it is slow cooled. Paraflow which purports to be made under U. S. Patent 1,815,022 suflers the disadvantage that only with slow chilling does it yield low pour tests as will be seen in the following table. A midcontinent lubricating oil of S. A. E. 40 grade was .treated with 1% Paraflow" and also with and 1% of my improved depressor. The samples were chilled in three ways, first by the slow meth-- od requiring about four hours to reach the minimum temperature, then by the A. S. T. M. method, and third by the shock method. The results were as follows:

(A) Depressor made by condensation without diluent and extraction from sludge with hexane; (B) samebut extraction with carbon tetrachloride.

The procedure for carrying out the slow chilling method is the same as the A. S. T. M. procedure for pour test determination with regard to the method of preliminarily heating the oil to a temperature of 115 F. in a bath at 120 F. followed by cooling to 90 F. in a bath at 70 F. From this 1 5 point on the sample is cooled in an air bath surrounded by a cooling bath in the same apparatus as employed for A. S. T. M. pour test determinations. The temperature. of the cooling bath, however, is maintained from 5 to 10 degrees below the temperature of the oil sample throughout the cooling operation. About four hours are necessary to chill the oil to its solid point, thus allowing a long time for the growth of wax crystals.

In the shock chilling method the sample is placed in the A. S. T. M. apparatusbut the surrounding bath-is maintained at 60 to 70" F. instead of at 15 to 30 below the expected solid point of the oil as in the A. S. T. M. determination. For oils of low solid point it is obvious that the shock chilling method will not difier appreciably from the standard A. S. T. M. method.

In all cases the cold test temperatures referred to are the solid points" which are more precise than A. S. T. M. pour points, which are even 5 readings above said solid points.

My improved pour point depressor is about two or three times as effective as Paraflow for lowering the pour point of heavy oils. S. A. E. 50

grade motor oil prepared from Salt-Creek crude which had a solid test of 20 F. was treated with 2% of Parailow" and then had a solid test of +15 F., whereas when treated with the same quantity of my improved product the solid test fell to -5 F. In the case of a mid-continent motor oil of S. A. E. 50 grade, having a-solid test of 30 E, /z% of my improved depressor lowered the solid test to 0 F., whereas 1% of Paraflow gave a solid test of +25 F., only 5 lower than that of the original oil. The solid test of No. 1 bright stock derived from midcontinent crude oil was entirely unaffected by the addition of 2% of the prior art pour test depressor, whereas the addition of 2% of my improved product lowered the solid test from 35 F. to 15 F.

While I have described in detail preferred embodiments of my invention it should be understood that I do not limit myself to the details hereinabove set forth except as defined by the following claims, which should be construed as broadly as the prior art will permit.

- I claim:

l. The method of preparing pour point depressors which comprises heating a mixture of a halogenated heavy hydrocarbon of a class which consists of paraiiin, petrolatum, Montan wax, ozocerite wax, and heavy paramn oils with an aromatic compound of a class which consists of naphthalene, diphenyl, chlorinated diphenyl, fluorene, phenanthrene, anthracene and coal-tar residues to reaction temperatures, subsequently adding aluminum chloride thereto, stirring the warm mixture during the addition of aluminum chloride, maintaining the mixture of aluminum chloride with the halogenated heavy hydrocarbons and the aromatic compound at reaction temperature till the reaction is substantially complete, extracting the pour point depressor from the aluminum chloride sludge by means of an organic solvent, neutralizing the extract, and removing the solvent and impurities from the neutralized extract.

2. The method of preparing a pour point depressor containing about 2 to 10 percent of chemically combined chlorine in which a chlorinated hydrocarbon of a class which consists of parafiin, petrolatum, Montan wax, ozocerite wax. ,and heavy paraflin oils is condensed with an aromatic hydrocarbon of a class which consists of naphthalene, diphenyl, chlorinated diphenyl, fluorene, phenanthrene, anthracene and coal tar residues, which method comprises mixing an aromatic hydrocarbon with a chlorinated paraflin hydrocarbon and subsequently adding aluminum chloride to said mixture under conditions of time and temperature to effect a condensation reaction.

3. The method of claim 2 wherein the reaction is carried out in the presence of a chlorinated hydrocarbon diluent.

4. The method of making a pour test depressor which willbe efiective in heavy oils, which method comprises heating a mixture of a chlorinated wax with naphthalene to reaction temperature, adding aluminum chloride to the heated mixture, agitating the mixture during the addition of the aluminum chloride and separating the resultant pour point depressor from sludge and impurities.

5. The method of claim 4 wherein the reaction is effected in the absence of diluent.

6. The method of claim 4 wherein the reaction is effected in the presence of a halogenated hydrocarbon diluent.

8. A wax-containing mineral 7. A pour point depressor which is eifective in 1 small amount in light oils, which is eflective in shock chilling, and which is'eflective in heavy oils which depressor comprises an aromatic hydrocarbon nucleus having long side chains and characterized by a stably bound chlorine content of about 2 to 10 percent.

lubricating oil which would normally have a high pour point in combination with a small amount, not substantially exceeding 1%, of a pour point depressor characterized by an aromatic nucleus, long side chains, and a stably bound chlorine content of about 2 to 10%.

9. The method of making a pour test depressor which is eflective in heavy oils, which method comprises mixing about parts of chlorinated wax with about 10 parts of naphthalene, heating this mixture to a temperature of at least 130' 1"" agitating the mixture, adding about 10 parts of aluminum chloride to the hot mixture while it is being continuously agitated, the addition of the aluminum chloride requiring about fifteen to thirty minutes and being slow enough to keep the reaction under control, maintaining the agitation after the aluminum chloride is added until the reaction is substantially complete for a period of about one-half to four hours, separating and removing. the condensation products from the sludge, neutralizing the condensation products and removing water soluble compounds and loosely bound chlorine compounds from the neutralized condensation products.

10. The method of making a pour test .depressor which will be effective in heavy oils, which no method comprises mixing a large amount of chlorinated wax with a small amount of naphthalene, heating and agitating the mixture, slowly adding to the hot mixture with constant agitation a small amount of aluminum chloride, the rate of adding the aluminum chloride being slow enough to keep the action undercontrol, the ad--' dition thereof requiring about fifteen to thirty minutes, continuing the addition of the aluminum chloride and maintaining the reaction mixo ture at an elevated temperature for a period of about one to four hours, removing the condensation products produced by the reaction-from the sludge produced thereby, neutralizing said condensation products and removing water soluble 12 compounds and loosely bound chlorine compounds therefrom.

v11. The method of claim 10, which includes the step of extracting condensation products from sludge by means of an organic solventhavmg not more than two carbon atoms, and subsequently distilling said solvent from said condensation products.

12. The combination of claim 10 wherein the aluminum chloride is added as a slurry in a halo- 5 genated organic solvent of not more than two carbon atoms.

13. An S. A. E. 50 grade lubricating oil con-.' taining wax, in combination with a small amount of a pour point depressor characterized by an aromatic nucleus, long side chains, and a stably bound chlorine content of about two per cent to ten per cent.

14. The method of making a pour test depressor, which comprises admixing an aromatic compound of the class which consists of naphthalene, anthracene, diphenyl, fluorene, phenanthrene, and coal tar residues with a small amount of a halogenated wax of the class which consists of paraiiln, petrolatum, Montan and ozoceing the solvent extracted mixture and distilling the solvent from the condensation products.

15. The method of claim 2 wherein the chlorinated paraflin hydrocarbon contains about 14% to 15% chlorine.

16. The method of claim 4 wherein the chlorinated wax contains about 14% to 15% chlorine.

1'1. The method of claim 9 wherein the chlorinated wax contains about 14% to 15% chlorine.

FREDERICK H. MACLAREN.

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